Acts of terrorism are not a new threat to the Nation’s capital, Washington, DC. However, it was not until the 1980's that any such incidents evoked heightened security around the White House which culminated in the closing of the section of Pennsylvania Avenue directly in front of the Executive Mansion in 1995. The study presented in this report, sponsored by the nonprofit, nonpartisan organization, Federal City Council, assesses how Pennsylvania Avenue could be reopened without compromising the safety and security of the President. It examines the content and circumstances that influenced the decision to close Pennsylvania Avenue and to assess that decision’s continued validity and appropriateness in light of developments, including trends in terrorism and counterterrorism that have occurred since 1995. The research was attained from open sources only, such as published books, secondary sources (newspapers), public government documents, on-the-record interviews with Federal law enforcement officials, architects, and members of local business men’s and citizens’ associations. Principle findings and conclusions of the study include: (1) the 1995 explosion at the Murrah Building in Oklahoma City may have less relevance than has been commonly assumed to the possibility of a similar attack directed against the White House; (2) the decision to close the section of Pennsylvania Avenue seems to have been regarded as permanent, thereby causing no attempts made to take advantage of new technologies and possible innovative approaches to physical security developed since 1995; (3) given the enhanced preparedness, through increased attention, larger budgets, and greater numbers of law enforcement and intelligence personnel there should be as great a factor in security planning and design; (4) justifications for Pennsylvania Avenue’s continued closure now extend beyond assuring the safety of the President and his family from truck-bomb attacks; (5) the extraordinary security measures in place at the White House could, in fact, displace terrorist threats onto other symbolic, but less extensively protected targets; (6) a comprehensive, independent examination should be undertaken to determine whether the 800-foot setback defined by the Secret Service is the absolute minimum distance required to adequately protect the White House; and (7) various proposed measures could secure the President’s personal protection from catastrophic truck-bomb threats while still permitting open access and unrestricted freedom of movement around the White House. Appendices A-B and references